1. The Field of the Invention
The field of the invention relates to an improved extractor and method for extraction of liquid from mashes, sludges or pulp bearing slurries.
2. Description of the Prior Art
The prior art is typified by several methods of and devices for extraction, expressment or deliquification of mashes, sludges or pulp bearing slurries. Generally speaking four categories are perceived. Oldest is the screw type press in which mash, the macerated, chopped or otherwise dismembered animal or vegetable material (apples, grapes, corn, fish) or biodegradable waste is placed in a drum or barrel-like container and compressed by a downwardly directed platen attached to a feed screw. Liquid, i.e. juice, oil, water, is exuded or expressed therefrom by pressure and drained off through perforations in the barrel or through slats. U.S. Pat. Nos. 332,044 to Caldwell, et. al. (1861) and 48,657 to Clayton, et. al. (1865) are typical of the kind. Another major type of extraction system involves disposition of the mash into a tapered feed screw which passes the mash through compression members which apply exudation pressure or expressing force to the liquid bearing material and cause the dried residue to be expelled continuously from the tapered end of the screw as gravity removes the liquid portion. U.S. Pat. No. 19,421 to Helton (1858); U.S. Pat. No. 508,958 to Middleton (1893); U.S. Pat. No. 2,360,984 to Schmitz (1942); U.S. Pat. No. 3,207,061 to Zaromb (1965) and U.S. Pat. No. 4,385,553, to Ihara (1983) typify this configuration. Manufacturers such as Vetters, Reitz, Jones and Sajo are representative of current commercial suppliers of this technology. Other advanced modern devices dealing with mash, as well suited to sludges and pulp bearing slurries, utilize intermittently bolted porous transport belts or those which move continuously. The material to be deliquified, carried on the belt, is compressed in sections intermittently by halting the belt in a defined deliquification zone, and downwardly directing reciprocating platen of a given size over a liquid collector which receives the expressed portion leaving dry residue on the belt. In a variation the belts may be driven continuously between pressure rolls. The products of Bucher-Guyer, SA, Niederweningen, Switzerland, see, a typical, U.S. Pat. Nos. 3,207,064, 3,541,951 and 3,951,058, all to Bucher-Guyer and 4,586,430 (1986) assigned to Atlas Pacific, are prominent. U.S. Pat. No. 235,198 to Bell (1880); the work of Vernsten set forth in U.S. Pat. Nos. 921,921 (1909) and 1,032,167 (1912); U.S. Pat. No. 1,296,112 to Peiler (1919); U.S. Pat. No. 1,798,555 to Pipkin (1930); and U.S. Pat. No. 3,273,492 to Justus (1966) are of interest. In this configuration the liquid is exuded through porosities in the belt in to a collector and the dried residue is scraped from the belt. In the case of pomace, to improve yield and prevent circular shear, additives called press aids such as rice hulls, shredded paper or other fibrous materials are mixed with the mash, prior to compression. Other methods utilize rotating drums of various configurations to accomplish expressment of the liquid into the drum's interior for collection such as U.S. Pat. No. 670,963 to Logemann, et. al. (1901); U.S. Pat. Nos. 1,238,289 to Hare (1917) and 3,478,796 to Rafanelli (1969) or the reverse, e.g. loading the drum interiorly and by rotary or compression forces from within the drum causing the liquid to be exuded exteriorly for collection with the dried residue removed from the drum in batches thereafter. See U.S. Pat. No. 4,191,103 to Wettlaufer and the products of Bucher-Guyer as typified in U.S. Pat. Nos. 4,106,404, 4,273,000, 4,837,634, 4,607,570, 4,410,051 and 4,151,785, all to Bucher-Guyer. U.S. Pat. No. 2,099,739 to Jenkins (1937) shows rolls inside one another to accomplish a similar purpose.
Passing mash between a driver roll and a counter-rotating hard surfaced idler roll in which the idler roll provides exudation pressure and the driver liquid separation is also known and it is nearer in art to the singular category into which the present invention falls. '963 to Logemann, et. al., although quite old and which typifies basic unresolved problems in the prior art, discloses a spring loaded compression roll with a hard surface disposed superiorly to a receptacle roll with a perforated outer surface through which into radially disposed, shaft abutting compartments liquid is expressed from side-fed material in a hopper situated at the nip point. The compartments are partially cleared of liquid through the roll ends by suction as they pass an exit port located above the receptacle rolls' axis.
Liquid is otherwise unrestrained and can counter-flow into the compartments or exteriorly by gravity during rotation. In addition, devices of the type will clog randomly if the top surface is merely an array of holes. If the surface is covered, the covering material soon loads with solids and becomes useless without down time to change it. By configuration, in the '963 type, substantial liquid must remain in each compartment or drain through the covering taking debris along with it. The surface material can never truly dry and is not susceptible to practical removal. Additionally, the shear forces from a hard compression roll will rupture cellular tissue and make for a recovered liquid with substantially turbidity.
Other dewatering arts such as is found in paper manufacture or the liquor separation and concentration utilized in the sugar cane processing art provide answers to some of the problems created in this area. None approach or solve with the effectiveness of the present invention similar problems notwithstanding their efficacy in these entirely unrelated purposes. See U.S. Pat. No. Re. 2,499 to Fassler, et. al. (1867); U.S. Pat. Nos. 949,787 to Wheat (1910) and 1,006,990 to Warren (1911). The commercial products of Atlas-Pacific, Mearelli as represented by Orchard Equipment and Supply Co., Conway, Mass. 01341, J and D Products and Wilmes also provide some insight to current practice in the mask deliquification art.
U.S. Pat. No. 817,930 to Nelson (1906); U.S. Pat. No. 1,834,852 to Kutter (1931); U.S. Pat. No. 1,908,519 to Leonard (1933); U.S. Pat. No. 3,238,866 to Strindlund (1966); U.S. Pat. No. 3,257,668 to Kusters, et. al. (1970); U.S. Pat. No. 4,378,253 to Bovet (1983); U.S. Pat. No. 4,391,026 to Casey, et al. (1983) and U.S. Pat. No. 4,559,106 to Skytta, et al. (1985) have been read with interest but are found to be unresponsive to the present claims.
Problems created by clogging of the mechanism with pulp or debris, sanitary control, batch processing, incomplete removal from the liquid of cellular material, less than satisfactory yield of expressed liquid per unit of weight and excessive shear to cellular tissue where applicable, which creates undesirable turbidity, unwanted fermentation or poor tasting liquid are current problems in the art. These are solved by the apparatus and method of the present invention.